[CBO guideline 'Deep venous thrombosis and pulmonary embolism'; revision of earlier guidelines].
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Algorithms↗
Biomedical subjects
P M Pattynama
Publications and source records attributed to P M Pattynama.
Tumor diameter and volume assessed by magnetic resonance imaging in the prediction of outcome for invasive cervical cancer.
OBJECTIVE: The aim of this study was to evaluate the predictive value of pretherapeutic magnetic resonance imaging (MRI)-based measurements of tumor diameter and volume with regard to recurrent disease. METHODS: MRI on 0.5- or 1.5-T scanners was performed in 126 consecutive women with invasive carcinoma of the uterine cervix. Initial tumor diameter and volume were determined on T(2)-weighted images; volume was calculated by the standard technique of multiplying the sum of the areas by the slice thickness. Patients were treated by radical surgery, radiotherapy, or a combined approach based on clinical International Federation of Gynecology and Obstetrics (FIGO) stage and individual patient criteria. Clinical data (patient age and FIGO stage), MRI-derived tumor dimensions (diameter and volume), and histological findings (tumor invasion depth and lymph-node involvement) were associated and linked to patient outcome. RESULTS: MRI-based tumor diameter correlated strongly with histological tumor invasion depth and lymph-node status (P < 0.01 and P = 0.01) while tumor volume on MRI was significantly associated only with tumor invasion depth into adjacent tissues (P < 0.01). Univariate analysis demonstrated graphically that MRI-derived tumor diameter and volume and clinical FIGO stage are associated with progression-free survival. Correlation analysis showed a strong association between MRI-derived tumor diameter and volume on MRI (r = 68%, P < 0.01) and also demonstrated a correlation between tumor diameter on MRI and FIGO stage Ib (Ib1 versus Ib2) cervical tumors (r = 46.7%, P < 0.01). CONCLUSION: Tumor diameter and volume, determined by pretreatment MRI examinations, predict progression-free survival for patients with invasive cervical carcinoma. This study demonstrates the value of MRI as an adjunct to clinical evaluation of invasive cervical cancer, providing more complete assessment of morphological risk factors important in patient prognosis and treatment planning.
Adult↗
Incidental renal artery stenosis in peripheral vascular disease: a case for treatment?
BACKGROUND: Renal artery stenosis (RAS) is frequently encountered as an incidental finding in peripheral vascular disease. We assessed whether revascularization is indicated to prevent the practical consequences of end-stage renal failure, that is, the need for renal replacement therapy. METHODS: In a retrospective study, a cohort of consecutive patients was followed who had undergone angiography 8 to 10 years previously for peripheral artery disease. Patients with untreated incidental RAS of > or =50% diameter stenosis (68.8 +/- 9.8 years, mean +/- SD) were compared with regard to the prevalence of renal replacement therapy to controls without RAS who were matched for age and gender. RESULTS: RAS was present in 126 of 386 evaluable patients (33%). None of these patients required renal replacement therapy during the 10-year follow-up. Serum creatinine values remained stable during follow-up. CONCLUSIONS: Incidental RAS is frequently seen in patients with peripheral vascular disease. If left untreated, incidental RAS seems not to result in end-stage renal failure or in a need for renal replacement therapy. Revascularization with the aim to prevent end-stage renal failure seems less indicated, and further prospective studies are indicated to elucidate this issue.
Aged↗
Contrast-enhanced spiral computed tomography of the pulmonary arteries: an overview.
Spiral computed tomography is a new noninvasive diagnostic test for pulmonary embolism. The method provides tomographic images of the thorax in the axial plane, which depict the thoracic wall, the mediastinum, the lungs, and the pulmonary vessels. Thrombotic emboli in the vessels are seen as intraluminal filling defects in the contrast-enhanced pulmonary arteries. The physical principles of spiral computed tomography and several technical considerations concerning image quality will be briefly discussed. The accuracy of spiral computed tomography in the detection of pulmonary embolism is discussed by way of an overview of published validation and clinical outcome studies encompassing spiral computed tomography and the diagnosis of pulmonary embolism.
Contrast Media↗
Second-generation, subsecond multislice computed-tomography: advancing the role of helical CT pulmonary angiography in suspected pulmonary embolism.
Advancements in computed tomography (CT) have led to the development of noninvasive helical CT of the pulmonary arteries as a diagnostic tool in patients with suspected pulmonary embolism (PE). The first-generation, single-slice CT scanners were capable of acquiring one 3-mm-thick imaging section per second. As a further technical evolution of helical CT, multislice CT scanners now allow simultaneous acquisition of eight slices per second. This increased imaging speed can be used to advantage by scanning the entire thorax with 1-mm-thin imaging sections during a single breath-hold. Because of the increased spatial resolution and increased robustness to motion artifacts of multislice CT, the pulmonary arteries can now be accurately depicted up to the fifth order branches. In comparison with single-slice CT, this holds the promise of better detection of small subsegmental PE and thus, increased accuracy to detect and rule out PE. A few recent management studies suggest that single-slice CT can be used as an accurate cornerstone in the diagnostic work-up of suspected PE-a concept that will be further enhanced with multislice helical CT.
Algorithms↗
Meaning of a helical CT angiogram negative for pulmonary embolism.
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Angiography↗
A precious metal alloy for construction of MR imaging-compatible balloon-expandable vascular stents.
The authors developed ABI alloy, which mechanically resembles stainless steel 316. The main elements of ABI alloy are palladium and silver. Magnetic resonance (MR) images and radiographs of ABI alloy and stainless steel 316 stent models and of nitinol, tantalum, and Elgiloy stents were compared. ABI alloy showed the least MR imaging artifacts and was more radiopaque than stainless steel 316. ABI alloy has the potential to replace stainless steel 316 for construction of balloon-expandable MR imaging-compatible stents.
Alloys↗
Intravascular ultrasound evidence for stabilization of compensatory enlargement of the femoropopliteal segment after endograft placement.
PURPOSE: To document whether the vasodilatory response seen at the anastomotic segment 6 months after placement of a balloon-expandable endograft in the femoropopliteal segment progresses between 6 and 24 months. METHODS: Twelve patients (9 men; median age 65 years, range 47-75) treated with an investigational polytetrafluoroethylene (PTFE) endograft for obstructive disease of the femoropopliteal segment were studied with intravascular ultrasound (IVUS) immediately after placement and at 6 months (first follow-up period) and 24 months (second follow-up period). Matched IVUS cross sections derived from the endograft and the anastomotic segment were analyzed for changes in lumen (LA), vessel (VA), and plaque areas (PLA). RESULTS: Five patients had complete IVUS surveillance at both the first (mean 8 months, range 7-9) and second (mean 25 months, range 23-26) follow-up periods; 1 patient was lost to follow-up during the second interval, and another 6 were excluded owing to graft occlusion (n = 4) or no IVUS surveillance available (n = 2) during the second follow-up period. Matched IVUS cross sections derived from the endograft showed no significant change in LA during both follow-up periods (-8% and +1%, respectively). There was no evidence for intimal hyperplasia or endograft recoil. During both follow-up periods, IVUS cross sections derived from the anastomotic segment revealed significant increases in LA (+37% and +8%, respectively) and VA (+26% and +6%, respectively) (both p < 0.05). The change in PLA during both follow-up periods was not significant (+13% and +3%, respectively). CONCLUSIONS: The PTFE endograft seems to inhibit both intimal hyperplasia and constrictive remodeling. The short-term (6-month) vascular dilatory response seen at the anastomotic segment tends to stabilize at 2 years. Therefore, this endovascular anastomosis acts as an "ideal" end-to-end anastomosis.
Aged↗
[Cyanosis and liver cirrhosis: hepatopulmonary syndrome].
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Cyanosis↗
[Treatment of non-resectable liver tumors with percutaneous interstitial laser coagulation while interrupting blood circulation to the liver].
OBJECTIVE: To evaluate, in patients with hepatocellular carcinoma or colorectal carcinoma disseminated to the liver, treatment with interstitial laser coagulation (ILC) during temporary occlusion of vascular inflow in the liver: feasibility, complications and initial tumour response. DESIGN: Prospective, descriptive. METHODS: Patients were included if their tumours were surgically irresectable and smaller than 4 cm in diameter and did not exceed a number of 3. ILC was performed under general anaesthesia, basically via a percutaneous approach. Vascular inflow was occluded during laser treatment. Twenty-four hours after ILC a triphasic spiral CT was performed to assess the result of the treatment. RESULTS: In 10 patients 14 hepatic tumours were lasered in 12 treatment sessions (10 percutaneous and 2 at laparotomy). After 5 treatment sessions, complications were observed of which pain at the insertion site of the catheters was the most frequent. For 6 out of the 10 patients with percutaneous procedures, discharge was within 24 hours after ILC. Nine out of the 14 tumours (65%) were completely coagulated. CONCLUSION: ILC with vascular inflow occlusion is a safe and feasible technique that can be performed during a short hospital stay. Initial tumour response is 65% and these results justify determination of duration of response in a larger group of patients.
Aged↗
The use of carbon dioxide in magnetic resonance angiography: a new type of black blood imaging.
The injection of boluses of carbon dioxide (CO(2)) during T1-weighted magnetic resonance angiography (MRA) resulted in sharp depiction of the vascular lumen during the performance of in vitro and in vivo animal experiments. We propose the use of the low-cost, relatively safe CO(2) as a negative contrast agent for MRA and speculate on its use in future interventional MRA.
Animals↗
Effect of MRI on therapeutic decisions in invasive cervical carcinoma. Direct comparison with the pelvic examination as a preperative test.
OBJECTIVES: Our aim was to compare magnetic resonance imaging (MRI) with the current standard clinical practice (pelvic examination including general anesthesia in selected patients) with regard to treatment planning in invasive cervical carcinoma. It was of particular interest to compare the accuracy of both methods for allocating the patients to the appropriate treatment modality: surgery versus primary radiotherapy. METHODS: One hundred and three consecutive patients with primary invasive cervical carcinoma underwent both MRI at 1.5 T and pelvic examination. The gold standard for comparing treatment decisions was based on the surgico-pathologic data: tumor confined to the cervix (treatment decision for surgery) or extracervical tumor spread (treatment decision for primary radiotherapy). RESULTS: A gold standard was available in 91 patients. The pelvic examination made correct treatment decisions in 89% of patients. However, the sensitivity for extracervical spread was only 44% (8/18 patients). MRI was better at identifying extracervical tumor spread: 67 and 89% for observers 1 and 2, respectively. MRI, however, had more false positive results and correct treatment decisions were made in 69-84% of patients (observer 1, 76/91; observer 2, 63/91). CONCLUSION: Treatment decisions based on the pelvic examination were correct in 89%, with MRI not bringing improvement. MRI, however, is better in diagnosing extracervical spread, but at the cost of more false positives.
Adult↗
Suspected pulmonary embolism: prevalence and anatomic distribution in 487 consecutive patients. Advances in New Technologies Evaluating the Localisation of Pulmonary Embolism (ANTELOPE) Group.
PURPOSE: To evaluate the prevalence and anatomic distribution of pulmonary embolism (PE) in a group of consecutive patients clinically suspected of having PE. MATERIALS AND METHODS: Four hundred eighty-seven consecutive patients clinically suspected of having PE were examined in six Dutch hospitals from May 1997 through March 1998. Patients underwent ventilation-perfusion (V-P) scintigraphy, spiral computed tomographic (CT) angiography, and/or digital subtraction pulmonary angiography according to a strict diagnostic protocol. Independent readers reviewed all of the diagnostic image studies in centralized readings. The largest pulmonary arterial branch in which PE was detected was recorded. RESULTS: The prevalence of PE was 27% (130 of 487 patients). There was a significant difference in PE size between the high-probability and nondiagnostic V-P scans: The high-probability scans tended to depict larger emboli, but they also showed small subsegmental emboli. Twenty-nine (22%) of 130 patients had subsegmental PE; 23 of these 29 patients had a high-probability V-P scan. CONCLUSION: The largest pulmonary arterial branch with PE was central or lobar in 66 (51%), segmental in 35 (27%), and isolated subsegmental in 29 (22%) patients.
Adult↗
Exclusion and diagnosis of pulmonary embolism by a rapid ELISA D-dimer test and noninvasive imaging techniques within the context of a clinical model.
A negative rapid ELISA D-dimer test alone in out-patients with a low to moderate clinical probability (CP) on pulmonary embolism (PE) is predicted to safely exclude pulmonary embolism. The combination of a negative rapid ELISA D-dimer test and a low to moderate CP on PE followed by compression ultrasonography (CUS) for the detection of deep vein thrombosis (DVT) is safe and cost-effective as it reduces the need for noninvasive imaging techniques to about 50% to 60% of outpatients with suspected PE. A high probability ventilation-perfusion (VP) scan or a positive spiral CT consistent with PE and the detection of DVT by CUS are currently considered to be clear indications for anticoagulant treatment. Subsequent pulmonary angiography (PA) is the gold standard diagnostic strategy to exclude or diagnose PE in suspected outpatients with a negative CUS, a positive rapid ELISA D-dimer test, and a nondiagnostic VP scan or negative spiral CT to prevent overtreatment with anticoagulants. However, the willingness of clinicians and the availability of resources to perform PA is restricted, a fact that has provided an impetus for clinical investigators to search for alternative noninvasive strategies to exclude or detect venous thromboembolism (VTE). Serial CUS testing for the detection of DVT in patients with a low to moderate CP on PE and a nondiagnostic VP scan or negative spiral CT is predicted to be safe and will reduce the need for PA to less than 10% or even less than 5%. This noninvasive serial CUS strategy restricts the need for invasive PA to a minor group of patients (< 5%) with the combination of a low CP on PE and high probability VP scan or the combination of a nondiagnostic VP scan or negative spiral CT and a high CP on PE. Prospective evaluations are warranted to implement and to validate the advantages and the disadvantages of the various combinations of noninvasive strategies and to compare serial CUS testing versus PA in randomized clinical management studies of outpatients with suspected pulmonary embolism.
Antifibrinolytic Agents↗
Observer dependency of the SimpliRed D-dimer assay in 81 consecutive patients with suspected pulmonary embolism.
The SimpliRed D-dimer assay is a whole blood agglutination test for the exclusion of pulmonary embolism (PE) and has been advocated as a reliable rapid bedside alternative to more time-consuming quantitative assays. However, widely differing negative predictive values (77-100%) are reported. This study assessed the intra- and interobserver variability as a possible cause for this wide accuracy range and evaluated the accuracy of the SimpliRed test in 81 consecutive patients with clinically suspected PE. Absolute D-dimer concentration was measured using the Tinaquant (Roche Diagnostics GmbH, Mannheim, Germany) assay. Every assay was immediately scored by one observer and then photographed. Photos were randomised and read twice by two other independent observers. The intraobserver reproducibility was good: kappa=0.81 and 0.73. However, we found poor interobserver reproducibility with kappa=0.47. This seems due to the fact that the SimpliRed test proved difficult to interpret in the 0.3-1.3 microg/mL plasma concentration D-dimer range, which contained 32/81 (40%) patients, 8 of whom had PE. Using pulmonary angiograms and ventilation perfusion lung scans with a concurrent spiral computed tomography scan as a gold standard (25 patients had PE), SimpliRed's accuracy to exclude PE was moderate, with negative predictive values of 0.78 and 0.84. In particular, the two observers scored the SimpliRed test as normal in 12 of 25 and 5 of 25 patients with proven PE. We conclude that SimpliRed is strongly observer-dependent. This explains the varying sensitivities for the detection of venous thromboembolism as reported in previous studies.
Fibrin Fibrinogen Degradation Products↗
Intravascular ultrasound evidence for coarctation causing symptomatic renal artery stenosis.
BACKGROUND: A recent study of human cadaveric renal arteries revealed that renal artery narrowing could be due not only to atherosclerotic plaque compensated for by adaptive remodeling, but also to hitherto undescribed focal narrowing of an otherwise normal renal arterial wall (ie, coarctation). The present study investigated whether vessel coarctation could be identified in patients with symptomatic renal artery stenosis (RAS). METHODS AND RESULTS: Consecutive symptomatic patients with angiographically proven atherosclerotic RAS who were referred for stent placement were studied by 30-MHz intravascular ultrasound before intervention (n=18) or after predilatation (n=18). Analysis included assessment of the media-bounded area and plaque area (PLA) at the most stenotic site and at a distal reference site (most distal cross-section in the main renal artery with normal appearance). Coarctation was considered present whenever the target/reference media-bounded area was </=85%. Before intervention, coarctation was observed in 9 of 18 patients and adaptive remodeling in 9 of 18 patients. Coarctation lesions had a significantly smaller PLA than adaptive remodeled lesions (P=0.001). Similarly, despite predilatation, coarctation was seen in 8 of 18 patients who had significantly smaller PLAs (P=0. 008) when compared with those patients who had adaptive remodeled lesions. No differences in severity of RAS or angiographic or clinical parameters were observed. CONCLUSIONS: Low-plaque coarctation may cause a considerable proportion of symptomatic RAS, which is angiographically and clinically indistinguishable from plaque-rich RAS.
Arteriosclerosis↗
International differences in health care costs in Europe and the United States: Do these affect the cost-effectiveness of diagnostic strategies for pulmonary embolism?
The aim of this study was to assess whether potential differences in costs for diagnostic procedures and treatment of pulmonary embolism (PE) among European and U. S. hospitals alter the optimal cost-effective diagnostic strategy for PE. A standardized questionnaire was used to obtain cost data for the diagnosis and treatment of PE in participating European and U. S. hospitals. Costs for diagnostic tests and treatment of PE were then calculated in a standardized manner for all participating hospitals, from the hospital perspective. Costs were used in an existing cost-effectiveness analysis (CEA) model to determine the most cost-effective diagnostic strategy in participating hospitals. There were considerable differences in costs for diagnostic and therapeutic procedures for PE among the participating centers. These differences, however, did not affect the most cost-effective strategy based on incremental cost-effectiveness. In all hospitals the most cost-effective strategy appeared to be ultrasound followed by helical CT. International differences in cost of diagnostic and therapeutic procedures certainly exist and should be considered before applying a published CEA. Nevertheless, despite these cost differences, the diagnostic strategy for PE of ultrasound followed by helical CT appears most cost-effective.
Angiography↗
Right ventricular systolic function and ventricular interaction during acute embolisation of the left anterior descending coronary artery in sheep.
OBJECTIVE: Regional LV ischemia involving the septum affects LV systolic function and geometry. We investigated the effects of these changes on RV function and geometry. METHODS: In six closed-chest sheep end-systolic pressure-volume relationships (ESPVRs) were constructed from ventricular volumes, measured with magnetic resonance imaging (MRI) and matching intraventricular pressures, before and after selective embolisation of the left anterior descending coronary artery (LAD). The extent of myocardial ischemia was assessed post-mortem by coronary perfusion with Evans-Blue. Alterations in septal geometry were studied by measuring the curvature, segmental length and thickness of the septum in two midventricular (short-axis) MRI slices before and during ischemia. From these data, changes in LV and RV free wall segmental lengths were calculated. RESULTS: Selective embolisation of the LAD resulted in left ventricular ischemia (15 +/- 2.1% of the total LV) with 23% of the septum involved. Stroke volume did not change significantly, while LV systolic pressure decreased by 24 mmHg (p < 0.05). Although RV systolic function decreased to a significantly lesser extent than LV function (p < 0.01), systolic function of both ventricles diminished significantly as indicated by substantial rightward shifts of the ESPVRs: 121% for LV and 41% for RV (both p < 0.01). At mid-ventricular level and end-systole, the septum showed significant increases in its radius of curvature and segmental length (both p < 0.05), and a significant wall thinning (p < 0.01). Calculated end-systolic lengths of LV and RV free walls also increased, by 57 and 14% respectively. CONCLUSIONS: LAD embolisation not only results in a significantly diminished LV systolic function but also causes RV systolic function to decline significantly. Regional dysfunction by necessity entails global dysfunction as well. Analysis of ventricular geometry reveals that both the septum and the RV free wall increase their length, which plays an important role in the pathophysiology of diminished RV systolic function concomitant with reduced LV function.
Animals↗